Self-propelled road vehicle



Dec. 2, 1930.

E. T. .1..l TAPP l1,783,890

SELF PROPELLED ROAD VEHIGLE Filed Jan. 29, 1930 Patented Dec. 2, 1930 UNITED STATES ERNEST THOMAS JAMES TAPP, OF LONDON, ENGLAND SELF-PROPELLED ROAD VEHICLE Application led January 29, 1930, Serial No. 424,401, and in Great Britain November`5, 1928.

This invention' relates to self-propelled road vehicles of the type wherein the rear axles are attached to the chassis by compensating spring mountings.

Ag The objects of the invention are to provide a simple and effective device which, acting in conjunction with the springs and their attachments, Will relieve the said springs and their attachments of certain undesirable strains and at the same time allow freedom of movement to conform to road inequalities whilst keeping the direction of travel as constant as may be desirable and/or to prevent or o restrict, to desiredl limits, lateral movement of one axle relative to the other. To this end, one or more pairs of members, hereinafter referredto as tracking members,

arranged in the form of a V, are provided show in plan and elevation one form ofthe invention, and Figures 3 and 4 show similar views to Figures 1 and 2 showing a modified form of the invent-ion.

Referring first to Figures 1 and 2, the invention is shown as applied to a type of vehicle in which there are two driven axles a, a positioned longitudinall by torque tubes a2 and a3 respectively. 'lhe fore axle torque tube a2 is attached by means of a ball joint (not Shown) to the chassis, and the rear axle torque tube a3 is attached by a ball joint b to the rear of the fore axle a. The drive to the rear axle a is taken from an extended worm shaft in the fore axle a through a universal joint Working v.inside the ball joint b.

The said axles a, a are anchored by means -shaped stay rod or two4 of four shackles c1, c2, c3, c4, and pins d1, (l2, da, ci", to two springs e, e attached to the chassis near their centres by pivot joints s and s.

Stay rods f are of the Y formation with a ball g at the extremity of the stem. The said ball g rests in a socket in the cylindrical plunger h free to slide in a cylindrical guide y' fixed just in front of the differential case under the torque tube of the rear axle.

The other extremities of the rods f are formed into two eyes which are-attached by pinsv or bolts lr:A to two hinge pieces Z which in turn are secured by the two spring pins d2, d, these pins being of sufficient length to serve the double purpose of anchoring the springs e, e as well as the hinge pieces Z.

The said hinge pieces are employed to allow the rods f to spring without straining the pins d2, d4, and/or to simplify alignment on to the 7l. said pins.

Now since the two springs and axles form a rectangle as seen in lan, a force applied to yone corner of the said rectangle (as forinstance when a lateral thrust occurs against one wheel) will tend to make the rectangle assume a rhomboid formation with a consequent strain on the spring attachment due to distortion.

With the device in actionhowever,` a triangle is formed by the rods f on an imaginary base line joining d2 to d4.

It will be seen now that any side thrusts on d for instance, will be communicated by the apex of the said triangle to the other axle, 85,

thus preventing or limiting distortion. As it is necessar y to allow independent rocking action of eac axle to conform to road inequalities, and furtherl that the device should not act asa radius rod (this function being ful- 9 filled by the torque tube), the sliding ball joint is provided at the apex. Thus the device prevents or limits vrelative lateral distortion only and restricts no other movement.

The usual known methods of strengthening the torque tube by strut or torque rods is omitted for the sake of clearness.

Referring to Figures 3 and 4, the invention is shown as applied to a vehicle in which thek fore and rear axles are anchored to two pairs '10 of springs m, m, and m', m', by means of links n, n', connecting the ends of the springs m, m to each other and to the axles. The said springs are anchored to the chassls by means of blocks o working on a cross bar p.

In this example, the stay rods f pivot about the said cross bar p. The stem f2 of the Y-shaped stay rods is in the form of a. plain pin free to slide through the ball g which is free to turn in a socket r attached to the rear axle.

What I claim is 1. In a road vehicle a pair of rear axles, springs secured to said axles, pins securing said springs to one of said axles and having a portion extended to project from one side of said springs and in parallel relation to said mentioned axle, a rigid triangular member arranged between the axles, means havin bearing upon the extended portion of sai pins and hingedly connecting the base of said triangular member to said pins, and a longitudinally slidable joint pivotally connecting the apex of said triannfular member to the remaining axle, Whereiy transverse movement of one of said axles is transmitted through the triangular member to the other axle.

2. ln a road vehicle, a pair of rear axles, springs secured to said axles, pins securing said springs to one of said axles and having a portion extended to project from one side of said springs and in parallel relation to said mentioned axle, a rigid triangular member arranged between the axles, means having bearing upon the extended portion of said pins and hingedly connecting the base of said triangular member to the pins, an enlarged head formed with the apex of said triangular member, a hollow socket supported intermevdiately of and upon the remaining axle, a piston-like. member mounted for reci rocating movement Within said socket and aving rotatable engagement with the enlarged head upon the apex of the triangular member` whereby transverse movement'of one of said axles is transmitted through the triangular member to the other axle.

In testimony whereof he aifixes his signature.

ERNEST THOMAS JAMES TAPP. 

